Safety-valve for pneumatic tires.



PATENTED DEC. 4, 1906.

W. S. ARNOLD. SAFETY VALVE FOR PNEUMATIC TIRES.

APPLIOATION FILED JUNE 2, 1906.

' [NVENTOR W 06 WITNESSES.-

UNITED STATES PATENT OFFICE.

WILLIAM S. ARNOLD, OF SAN FRANCISCO. CALIFORNIA.

SAFETY-VALVE FOR PNEUMATIC TIR ES- Patented Dec. 4, 1906.

Application filed June 2, 1906. Serial No. 319,949-

for reventing the exp osion of such tires.

e object of the invention primarily is to provide a device adapted to escrewed to the threaded portion or nipple of the ordinaryinflating-valve of a tire and to actin conjunction with the valve-pin ofthe tire-valve to prevent" explosion of the tire from excessive pressurewithin, due to the expansion of the air in the tire from heat or fromother causes, such as striking a projection or depression in theroadway. I

A further object is to so construct the device that it can be readilyset to o erate at predetermined pressures to relieve t e strain on thetire when such predetermined pressure is exceeded.

One of the important and highly desirable features of the inventionabout to be described with regard to its utility is the con-,

struction that permits its application to tirevalves in common use bymerely removing the dust-cap andscrewing the device thereon, the safetydevice when applied taking the place of this cap.

Other objects and'advantages looking to cheapness, simplicity, anddurability are in view and will become apparent in the course of thefollowing description.

' In the drawings illustrating the invention, Figure I is a section of aportion of. a neurnatic tire and valve with the safety evice applied,the said device being also in section an occupying'a position justbefore being screwed down into operative engagement with the tire-valvepin, the tire-va ve being shown closed; 7 2 is asimilar view showing thedevice in its lowest position, with the rod of the safety device inengagement with the pin of the tire-valve, showing saidvalve 0 611; and3 is an enlarged sectional view oi the device, sho the valve in dottedines, with the screwhead for closing the upper end of the casing 'injuxtaposition to the casing.

Referring to the drawings, the numeral 1 indicates an ordinary pneumatictire fitted the raised position of with a valve-holder 2 and valve 3,having the usual pin 4 extending up into the threaded nipple 5.

The numeral fi-designates the improved valve-casing, which is interiorlythreaded at its lower end, as indicated at 7, which adapts it to bescrewed onto the nipple 5, Just above the threaded portion a valve-seat8 is formed having a central aperture 9 for the easy passage of thevalve-rod 10. This valve-rod is referably provided at its lower end witha sight enlargement 11, having a depression therein in w ich rests theupper end of the valve 4, and loosely surrounding the upper end of thisrod is a screw-plug12,-

between which and the valve 13, which is rigidly secured to the rod 10,is a spiral spring 14, that holds the valve 13 seated under normalconditions. The diameter of the valve 13 is a little less than that ofthe interior of the casing, and the aperture 9 is a little larger thanthe rod 10, thus allowing the air to (pass through the aperture aroundthe rod an through the space between the peripheig of the valve and thewall of the casing w e n the conditions are such as to operate thesafety device.

When the pressure in the tire exceeds the predetermined pressure or thepressure above which the device will operate, the tirevalve will beforced u wardly against the rod 10 and, together wit the ressure aroundthe tire-valve and beneath t e valve 13, will raise said rod and valve13 against the pressure of the spring 14, thus'permitting the air topass through the aperture 9 around the rod, under the valve, and out ofthe casing through perforations 15, made in the walls of said casing.

The central opening in the screw-plug 12 is of such size as to therprovided wit arecess 16 for the reception of a suitable spanner'by whichthe plu is screwed to any position in the threade reaching thescrew-plug to set it to relieve the ressure on the tirewhen the sameexceeds that which has been predetermined.

The tire is inflated orblown up in the usual manner, the valve thereinoperating in the ordinary way to prevent the escape of air. Assuming thetire to be blown to suflicient hardness and the pump connectionsremoved,

ermit the valve-rod to pass freely throu h it, and this plug is fur-fthe safety device,'which is set to operate at a pressure exceeding thatto which the tire has been blown, is secured to the nipple of thetire-valve and takes the place of the valve cap ordinarily employed. Inattaching the safety device 'as already suggested the tirevalve will beopened; but the pressure in the tire will not be sufficient to operatethe valve of the safety device under these conditions and the safetydevice will merely serve the purpose of the tire-valve, but will be inreadiness to operate and relieve the pressure on the tire when thepredetermined pressure has been exceeded.

-Of course it will be understoodthat it will be much simpler and cheaperto apply the described device to the nipple of the inflating-valve; butit is obvious that it may be permanently attached to a valve such asthat shown and a separate valve of'any approved construction used forinflating pur oses exclusively', which arrangement woul result inturning the Whole described device into one used exclusively for safetypurposes.

I claim I I 1. A safety pressure device for pneumatic tires comprising adetachable casing formed with a-valve-seat therein, an air-outletopening above the seat, a valve on said seat and means for holding saidvalve seated under normal tire-pressures, means for unseating andholdingthe tire-valve open to normally establish communication betweenthe tire and the casing below the valve-seat substan-.

3. In combination with the inflatin -valve of a pneumatic tire, a casingdetacha le for the purpose of inflating the tire, said casing having avalve-seatformed therein, the easing being provided with air-outletopenings above the seat, a valve on said seat, a spring pressing uponsaid valve, means forvarying the tension of the spring, and means forunseating and holding the tire-valve normally open, substantially as andfor the purposes set forth.

4. The combination with the valve of a proper to hold it open, asprilnigvpearing 1oln o 1 norma y the valve in the casing to closed, anda screw-plug in the top of the casing fortensioning the s ring to oldthe casin valve seated at dliferent predetermine tire-pressures.

5. The combinationwith a valve of apneumatic tire, of a casing havingair-openings therethrough and attached to the tire-valve, a valve-seatin said casing havin anopening therein whereby communicationlietween thetire and casing may be established, a screwplug in the top ofthe'casing, a rod working through said plug and carrying a valve restingon the seat and having an extension engaging the tire-valve proper tohold it open, a spring interposed between the valve and the screw-plug,whereby the valve in the casing is held normally seate substantially asdescribed.

In testimony whereof I am my signature in presence of two witnesses.WILLIAMS. ARNOLD. Witnesses:

TITIAN W. JOHNSON, J. JEROME Lmnrroo'r.

